1. Field of the Invention
The present invention relates to a solid state laser device utilizing a semiconductor laser as a light source for exciting a laser medium.
2. Description of the Prior Art
As a conventional solid state laser device, FIG. 3 illustrates a structure of a solid state laser device using an end-pumping system for constructing a resonator comprising an end surface of a laser medium and a mirror.
The solid state laser device comprises a pumping semiconductor laser 30 for oscillating a laser light as an excitation light, a collimator lens 31 for leading the laser light oscillated from the pumping semiconductor laser 30 to parallel rays, and a focusing lens 32 for focusing the laser light output via the collimator lens 31 and leading the focused laser light to a laser medium 33. The focusing lens 32 has a structure wherein a focus of the each parallel rays is positioned on a surface of the laser medium 33 or a slightly inner point thereof. Moreover, the solid state laser device includes the laser medium 33 for absorbing the laser light focused by the focusing lens 32, the laser medium 33 is composed of an Nd-YAG crystal in which a YAG (Yttrium Alminum Garnet) crystal is doped with Nd. An output mirror 34 positioned opposite to the laser medium 33 constructs an incident surface of the laser light emitted inductively in the laser medium 33, and an optical resonator 35 consists of the output mirror 34 and an end surface 331 of the laser medium 33. By the optical resonator 35, the laser light is confined between the laser medium and the output mirror 34, to be amplified by resonating. A part of the amplified light is output via the output mirror 34. In such a solid state laser device, the output surface of the laser light of the pumping semiconductor laser 30 is a reference plane, other component parts are positioned on an optical axis 36, and alignments are performed as a whole.
In the solid state laser device having the above structure, a life of the pumping semiconductor laser 30 is the shortest among those of all component parts which the solid state laser device comprises, such as the lens, the mirror, and the laser medium. Owing to an electrical surge, an excess current and a static electricity, there is the highest possibility wherein a trouble happens, whereby the pumping semiconductor laser 30 is often exchanged.
However, in the structure of the above solid state laser device, in case of exchanging the pumping semiconductor laser 30, the following steps are required: all component parts of the solid state laser device are disassembled into all pieces, the pumping semiconductor laser 30 is exchanged into new one before a laser light outgoing radiation surface of the pumping semiconductor laser 30 is utilized as the reference plane, and the all component parts, that is, the collimator lens 31, the focusing lens 32, the laser medium 33 and the output mirror 34 in order are aligned with the result that it takes much labor and long time to complete such a work. Consequently, it is difficult to complete an assembling operation because it takes a further long time to assemble the device with the number of component parts is increased.
The object of the present invention is to provide a solid state laser device wherein, in case that the pumping semiconductor laser is exchanged, the exchange, assembly and adjustment operations can be easily and efficiently performed.
In order to achieve the above object, the solid state laser device according to the present invention comprises a laser semiconductor for oscillating a laser light as a pumping light, an optical system for leading the laser light to parallel rays, a focusing lens for focusing the laser light led to the parallel rays by means of the optical system and leading the focused laser light to a laser medium, the laser medium for absorbing the laser light and outputting a spontaneous emission light and an optical resonator for confining the spontaneous emission light to make the laser light oscillated by means of an induced emission, wherein the solid state laser device includes a first housing for storing the laser semiconductor and the optical system wherein they are positioned on the same optical axis, and a second housing for storing the focusing lens, the laser medium and the optical resonator wherein they are positioned on the same optical axis, and the solid state laser device is characterized in that the housings are detachable.
Moreover, the second housing may be structurally provided with an output lens for outputting the laser light output by the optical resonator, as the parallel rays.
In addition, the optical resonator may structurally include an end surface of the laser medium and a partial transmittable mirror positioned opposite to the end surface.
Furthermore, as a concrete embodiment of the present invention, a wavelength converting element is disposed between the laser medium and the partial transmittable mirror included by the optical resonator, thereby allowing a structure of a wavelength-converting-type solid state laser device.
As mentioned above, the solid state laser device according to the present invention has a structure wherein the first and the second housings are only disposed at each predetermined position, thereby keeping a movable installation state. Moreover, in case of performing a maintenance such as exchanging the component parts disposed inside the housings, the exchange is operated in each unit, and it is proper simply to align the positions of the component parts inside the each housing. Consequently, it is not necessary to align the positions of the all component parts as a whole of the solid state laser device.
In other words, the each housing can be aligned so as to be served most efficiently in operation, excitation beams emitted from the first housing to the second housing are parallel by the collimator lens, whereby meeting each optical axis between two housings requires no high efficiency. For example, even if the optical axes are slightly shifted each other, or they intersect aslant, a tolerance of the alignment is wide with the result that it is easy to install the each housing.